Conventionally, in a sewage conduit and irrigation conduit, many reinforced concrete pipes (Hume pipe) are used.
In sewage and irrigation conduits built using reinforced concrete pipes, due to corrosion, abrasion and breakage caused from aging of concrete pipes, problems such as cave-in and water leakage have been increasing. Therefore, appropriate repair and renewal thereof based on appropriate diagnosis of the deterioration and the inspection result thereof are required.
In the diagnosis and inspection of the sewage and irrigation conduits, generally, in order to determine the order and construction method of repair and renewal work, it is required to classify the progression level of deterioration in a component segment constituting the drainage basin to be inspected, and it is necessary to detect the progression level of the deterioration in a quantitative manner.
Conventionally, in general, such a method, in which a visual check and an appearance inspection are carried out using a TV camera; and if necessary, a core is taken out to inspect solid state properties thereof, is carried out.
However, in the above-mentioned technique, only visible deterioration can be detected; accordingly, deterioration on the periphery and inside of the pipe cannot be detected. Additionally, it is impossible to detect the progression level of deterioration in an appropriate and quantitative manner, and it is necessary to take out a large amount of cores to collect quantitative data. Therefore, there arise such problems that the strength of the sewage or irrigation conduit is reduced, and significant manpower is required.
On the other hand, it has been considered to put the inspection methods used for concrete structures into use.
For example, systems, in which the width and depth of cracks are estimated using elastic waves, have been disclosed in Japanese Published Unexamined Patent Application No. H10-142200 and Japanese Published Unexamined Patent Application No. H09-269215. However, these systems are not satisfactory in workability. When these systems are applied to the inspection of a structure extending over a long distance such as sewage and irrigation conduits, it takes a considerably long time for the inspection.
The present invention has been proposed to solve the above-described problems. It is an object of the present invention to provide an inspection method for reinforced concrete pipes which, when inspecting the deterioration state of a reinforced concrete pipe constituting a sewage conduit, irrigation conduit or the like, is capable of increasing the efficiency of the inspection work as well as evaluating the progression level of deterioration in a quantitative manner, and an inspection apparatus suitable for carrying out such an inspection method.